The Way You Make Hair Blonde May Also Have Started Life

Some scientists believe hot vents deep under the ocean are the most likely site of the first life on Earth. NOAA Ocean Exploration & Research/Flickr

A staple of home medicine cabinets could have sparked the reactions that led to the very first life on the planet in the seafloor waters around small vents in Earth's crust, according to the pair of scientists behind a new paper published in the journal Royal Society Open Science. For the past few years, they've focused on trying to figure out whether the chemical hydrogen peroxide could have helped spur reactions leading to the very first lifelike compounds.

The study is based around the analogy of a toy train by arguing that setting was key: In order for these reactions to play out, they had to take place in a string of pores and tunnels found in certain kinds of rock, like those located near the hydrothermal vents where many scientists today think the very first life may have come into being. The authors believe this neighborhood structure helped foster the growth of longer, more complicated strings of atoms by offering slightly different environments in each of the train's cars.

Then, to get a sense of whether this whole idea could work, they built a model using randomly porous rock, which is more similar to what would have really been found on Earth than something with a uniform structure. It's still tricky to get even a tiny step closer to life—if the temperature or acidity changes too abruptly, it can end the whole series of reactions. But if those conditions only fluctuated within a set window, hydrogen peroxide could help build enzymes that break down compounds.

That's an important twist, since it might have prevented competition from any other equally promising reactions that were happening at the same time. "Evolution can be thought of as burning a succession of small bridges," lead author Rowena Ball, a chemist at the Australian National University, said in a press release. "But the first cellular life destroyed probably one of the most important bridges, the one that spanned the living and non-living molecular worlds."

But despite this new theory, there's a very real possibility that we will never know for sure how life first came into being, or even whether deep sea vents truly are the site of the very first life, which happened, the authors write, "at a place and under physical and chemical conditions, all of which are uncertain and virtually impossible to verify from any currently observable evidence."